Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Testing Apparatus And Method For Detecting A Contact Deficiency Of An
Electrically Conductive Connection
Field of the Invention
The invention relates to a testing apparatus for detecting a contact
deficiency of an electrically
conductive connection that is realized with several electrically conductive
system elements
having insulated and metallic components and services for conducting signals
or energy, and a
method for detecting a contact deficiency of an electrically conductive
connection that is adapted
for the testing of the electrically conductive system elements used for
conducting signals or
energy. It is intended for applications in which such connections need to be
produced in a very
precise and quality-responsive fashion in order to ensure the constant
availability and reliability
of the electrically conductive connections in the supply of energy to electric
consumers and/or
the transmission of information to control units or other devices, for
example, in aircraft. The
invention realizes a prophylactic testing of such electric cable connections
that are prefabricated
due to technological considerations and allows a reliable visual detection of
incorrectly
(defectively) produced cable connections without significantly technological
expenditures.
Background to the invention
It is generally known that vehicles such as land craft, watercraft or aircraft
are equipped with a
plurality of electric connections that need to be produced in a very precise
and quality-responsive
fashion for the initially cited reasons. Conventional cable connections, the
installation of which
is realized with copper cables, are quite frequently produced with copper
cables, the conductor of
which is respectively connected by crimping a metallic crimp type socket on
the stripped
conductor region with the aid of a suitable tool, wherein the electric
connection between to strip
conductor ends accommodated in the sockets is ensured, for example, by the
socket making
contact with the conductors. This contacting is predominantly realized with
said crimp
connection, wherein conventional systems may include this installation
technology. In order to
ensure that a reliable electric connection is produced, crimp type contact
sockets provided with a
recess in the form of an inspection hole are used, for example, in the
construction of aircraft, so
as to determine whether or not the copper conductors of two copper cables are
correctly
connected to one another by means of crimping. In this case, (only) a visual
inspection may be
carried out after the crimping process so as to ensure that the crimping
process was performed
properly, wherein the crimped conductor needs to be visible within the region
of the inspection
hole if the contact socket was properly crimped. Since visual errors of the
individual inspectors
or material defects on the contact socket or an inspection hole
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position that deviates from the predefined position (due to the defective
manufacture
of the contact socket), among other things, may never be ruled out, the
question
whether this testing technology actually suffices is not discussed in detail
because the
proposed invention pursues a profoundly different goal. Corresponding examples
of
such cable connections are illustrated in enclosed Figures 1 and 2 in order to
provide
the observer with a practical overview of the relevant design.
With respect to aircraft, the invention also takes into consideration
installations with
cables, the conductor material of which may result in a weight reduction,
namely
because any weight reduction is a desirable aspect, particularly in the
construction of
aircraft, for example, due to the attainable energy savings (kerosene
consumption)
and the extended range of the aircraft.
When utilizing a technology of this type that takes into account the
installation of
such weight-reducing cables in aircraft, it may be necessary to utilize
crimpable
contact sockets that do not contain an inspection hole. The reason for the
lack of the
inspection hole may be seen in that the contact areas of the connecting points
may
need to be hermetically sealed in order to reliably preclude any corrosion of
the
crimp connection and/or an increase of the electric contact resistances at the
contact
points. Corrosion may be caused by various types of materials (silver, copper,
nickel,
aluminum), wherein the reason for this corrosion may be seen in that the
connection(s) is (are) produced with (a) cable(s) and a contact socket of
different
conductive materials, as well as in the local influence of an electrolyte in
connection
with (occurring) humidity, for example, atmospheric humidity. In this respect,
in
conventional systems corroding contact(s) (surfaces) may lead to the failure
of the
connected devices and apparatuses or even entire systems, wherein this may, in
the
(undesirable) worst-case scenario, result in the complete failure of the
(correlating)
systems in the aircraft. The consumption of a corroded, current-carrying
contact
caused by an increased (growing) electric contact resistance may have fatal
consequences. The increase of the contact resistance at the contact points of
the
electric connection in question may therefore also be influenced by the
improper
crimping of the contact socket on the conductor regions to be connected. If
the
contact surface has excessively small dimensions, the current density
increases such
that said consumption may occur on the contact surfaces. If the contact socket
is
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improperly crimped such that the connecting element(s) (surfaces) are
insufficiently
contacted, it may be expected that any occurring vibrations, for example,
those of an aircraft,
will result in the failure of the devices, apparatuses or the entire system
connected with the
aid of this crimp connection. The aforementioned inferior contacting in a
conductor-crimp
type socket-conductor connection may be decisively influenced by the improper
crimping of
the contact(s) (surfaces) of the connecting elements and/or by the inadequate
insertion of the
cable(s) into the contact sockets, wherein in conventional systems these
inadequacies are
named under the term "contact deficiency" of the electrically conductive
connection. The
illustrations in enclosed Figures 3A, 3B, 3C and 4 show examples of a
connection that is
produced correctly or incorrectly, wherein a correctly produced connection
(correctly
stripped) is illustrated in Figure 3A. The incorrectly produced cable
connections shown in
Figures 3B (over-stripped), 3C and 4 (incorrectly cut and inserted cable)
elucidate the existing
need (appreciation) to solve (eliminate) the problem defined below.
Summary of the Invention
Among other things, it may be an object of the invention to make available an
efficient
solution for a testing apparatus and a method for detecting a contact
deficiency of an
electrically conductive connection, wherein said solution may make it possible
to verify
whether prefabricated cable connections or subsequently produced cable
connections as they
are required during repair procedures or adaptive modifications are produced
in a precise and
quality-responsive fashion. The invention may aim to disclose a reliable
visual detection of
incorrectly (defectively) produced cable connections, wherein the handling of
the testing
apparatus and the implementation of the method may be realized without
significant
technological expenditures.
In one aspect, the invention resides in a testing apparatus for detecting a
contact deficiency of
an electrically conductive connection that is realized with several
electrically conductive
system elements having insulated and metallic components and serves for
conducting signals
or energy, wherein the testing apparatus comprises: a measuring chamber; a
heat radiator; a
thermal image acquisition unit; and a thermal image reproduction unit; wherein
in the
measuring chamber the system components of the electrically conductive
connection are
positioned, wherein the system components are connected to one another in an
electrically
conductive fashion; wherein the heat radiator is supplied with energy; wherein
the transferred
thermal radiation of the heat radiator is emitted into the measuring chamber
and the thermal
radiation is directed toward the region of the system elements, such that a
thermal field of the
insulated
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and the metallic system components of these connected system elements is
generated,
wherein the thermal image acquisition unit is adapted for optically capturing
the generated
thermal field emitted by the heated insulated and metallic system components
of said
connected system elements and for realizing a signal conversion into a thermal
image of the
connected system elements; and wherein the thermal image reproduction unit is
adapted for
realizing a visual reproduction of the converted thermal image, wherein the
thermal image
acquisition unit and the thermal image reproduction unit are connected in an
information
technological manner.
In another aspect, the invention resides in a testing apparatus for detecting
a contact
deficiency of an electrically conductive connection that is realized with
several electrically
conductive system elements having insulated and metallic components and serves
for
conducting signals or energy, wherein the testing apparatus comprises: a
measuring chamber;
a heat radiator; a thermal image acquisition unit; and thermal image
reproduction unit;
wherein in the measuring chamber the system components of the connection are
positioned;
wherein the system components are connected to one another in an electrically
conductive
fashion, wherein the heat radiator for infrared light is supplied with a
constant current by a
generator, wherein the infrared light thermal radiation of said heat radiator
is transferred
transversely or horizontally or vertically or in a deflected fashion and is
directed toward the
region of the electrically conductive connection, such that a thermal field of
the insulated and
metallic system components of these connected system elements is generated by
the infrared
light thermal radiation, wherein the thermal image acquisition unit for
infrared light is
adapted for optically capturing the generated thermal field; and wherein the
thermal image
acquisition unit is adapted for realizing a signal conversion into an infrared
light thermal
image of the conductively connected system elements emitted by the heated
insulated and
metallic system components of these connected system elements; and wherein the
thermal
image reproduction unit for infrared light is adapted for realizing a visual
reproduction of a
digitally converted thermal image, wherein the thermal acquisition unit and
the thermal image
reproduction unit are connected in an information technological manner.
In another aspect, the invention resides in a method for detecting a contact
deficiency of an
electrically conductive connection that is adapted for the testing of the
electrically conductive
system elements used for conducting signals or energy; wherein several
serially connected
system elements are connected in an electrically conductive fashion by a crimp
connection at
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the connecting points of the system elements; wherein said method utilizes a
testing
apparatus, the functional scope of which comprises a measuring chamber, a heat
radiator, that
is supplied with energy and arranged within the latter, a thermal image
acquisition unit and a
thermal image reproduction unit that are connected in an information
technological manner;
and wherein the method comprises : a) positioning the system elements that are
serially
connected by crimp connections in the measuring chamber; subsequently b)
transferring
thermal radiation toward the region of the system elements in the measuring
chamber by the
heat radiator; subsequently c) transferring thermal energy of the thermal
radiation to insulated
and metallic system components of the connected system elements such that a
thermal field is
generated; subsequently d) optically capturing the thermal image acquisition
unit and
subsequently converting the generated thermal field by a signal conversion
into a thermal
image; and subsequently e) displaying a visual reproduction of the converted
thermal image
by the thermal image production unit.
According to an exemplary embodiment a testing apparatus for detecting a
contact deficiency
of an electrically conductive connection is provided wherein the testing
apparatus is realized
with several electrically conductive system elements for
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conducting signals or energy, wherein a measuring chamber is provided in which
are
positioned the system components of the connection that are connected to one
another in an electrically conductive fashion, wherein a heat radiator is
provided that
is supplied with energy and the transferred thermal radiation of which that is
emitted
into the measuring chamber is directed toward the region of the system
elements
such that a thermal field of the insulated and the metallic system components
of these
connected system elements is generated, wherein a thermal (image) acquisition
unit
is provided that serves for optically capturing the generated thermal field
emitted by
the heated insulated and metallic system components of these connected system
elements and for realizing a signal conversion into a thermal image of the
connected
system elements, and wherein a thermal (image) reproduction unit is provided
that
serves for realizing a visual reproduction of the converted thermal image,
with the
thermal (image) acquisition unit and the thermal (image) reproduction unit
being
connected in an information technological manner.
According to an exemplary embodiment a testing apparatus for detecting a
contact
deficiency of an electrically conductive connection is provided wherein the
testing
apparatus is realized with several electrically conductive system elements for
conducting signals or energy, wherein a measuring chamber is provided in which
are
positioned the system components of the connection that are connected to one
another in an electrically conductive fashion, wherein a heat radiator for
infrared
light is provided that is supplied with a constant current by a generator,
wherein the
infrared light thermal radiation of said heat radiator that is transferred
transversely or
horizontally or vertically or in a deflected fashion is directed toward the
region of the
electrically conductive connection such that a thermal field of the insulated
and
metallic system components of these connected system elements is generated by
the
infrared light thermal radiation, wherein a thermal (image) acquisition unit
for
infrared light is provided that serves for optically capturing the generated
thermal
field and for realizing a signal conversion into an infrared light thermal
image of the
conductively connected system elements emitted by the heated insulated and
metallic
system components of these connected system elements, and wherein a thermal
(image) reproduction unit for infrared light is provided that serves for
realizing a
visual reproduction of a digitally converged thermal image, with the thermal
(image)
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acquisition unit and the thermal (image) reproduction unit being connected in
an
information technological manner.
According to an exemplary embodiment a method for detecting a contact
deficiency
of an electrically conductive connection is provided that serves for the
testing of the
electrically conductive system elements used for conducting signals or energy,
wherein several serially connected system elements are connected in an
electrically
conductive fashion by means of a crimp connection at the connecting points of
the
system elements, wherein said method utilizes a testing apparatus, the
functional
scope of which comprises a measuring chamber, a heat radiator that is supplied
with
energy and arranged within the latter, a thermal (image) acquisition unit and
a
thermal (image) reproduction unit that are connected with respect to
information
technology, and
wherein the following steps are carried out:
a) the system elements that are serially connected by crimp connections are
positioned in the measuring chamber and subsequently
b) the heat radiator in the measuring chamber directs transferred thermal
radiation toward the region of the system elements, namely such that
subsequently
c) the insulated and metallic system components of the connected system
elements absorbs the transferred thermal energy of the thermal radiation
converting
to a thermal field and subsequently
d) the thermal (image) acquisition unit optically captures and subsequently
converts the generated thermal field by a signal conversion into a thermal
image and
subsequently
e) the thermal (image) production unit realizes a visual reproduction of the
converted thermal image.
At this point it has to be mentioned that the described testing apparatus may
also be
realized by means of further embodiments. Thereby, it is clear for a person
skilled in
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the art that the features described with these further embodiments may also be
combined with features of the embodiments described above and the embodiments
for the method for detecting a contact deficiency of an electrically
conductive
connection.
Brief Description of the Drawings
Below, for further explanation and for better understanding of the present
invention,
exemplary embodiments are described in more detail with reference to the
enclosed
drawings. In the drawings:
Figure 1, shows a cable connection with a copper conductor and a contact
socket;
Figure 2, shows the cable connection according to Figure 1 with an aluminum
conductor (with a copper and/or nickel coating of the bunched wires
of the aluminum conductor) that is accommodated within a silver
socket;
Figure 3A, shows a correctly produced cable connection according to Figure 1
with a conductor insulation of an electric conductor that is
accommodated at the beginning of the socket;
Figure 3B, shows a cable connection according to Figure 3A with several
contact
deficiencies;
Figure 3C, shows a different illustration of the cable connection according to
Figure 3B;
Figure 4, shows a detailed illustration of the cable connection according to
Figure 3C;
Figure 5, shows a physical illustration of a testing apparatus for testing
cable
connections;
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Figure 6, shows the block diagram of the testing apparatus according to Figure
5;
Figure 7, shows an embodiment of the testing apparatus according to Figure 5,
and
Figure 8, shows a modified embodiment of the testing apparatus according to
'Figure 5.
Detailed Description of Exemplary Embodiments
It should also be noted that the contact socket 71 in Figures 1 and 2 is
respectively
equipped with an inspection hole 75 that traditionally serves for visually
inspecting
(verifying) an electrically conductive connection 5 in the socket. In other
respects,
these conductor connections according to Figures 1-4 generally pertain to the
(conventionally implemented) state of the art while the testing of these
conductor
connections that is described below and carried out by means of the testing
apparatus
1 according to Figures 5-8 may aim to eliminate the deficiencies that are
(obviously)
inherent to traditionally utilized test technologies (in need of improvement)
according to Figures 1-4 (for testing such conductor connections). In order to
clearly
elucidate the problems inherent to this state of the art to a person skilled
in the art, a
few additional explanations deemed necessary for the better understanding of
the
following exemplary embodiments of the invention are provided below with
reference to Figures 1-4.
In conventional systems conventional conductor connection according to Figure
1
may be known. This connection features a contact socket 71, the socket cavity
72 of
which on the left side (clearly highlighted) is partitioned approximately in
the center
of the socket. Consequently, the thusly partitioned socket region (socket
cavity 72)
may be compared with a socket outlet 74 that is closed in the center of the
socket and
at which the contact socket 71 (shown on the left) ends (approximately above a
socket flange 76 on the circumference of the socket), wherein the right sleeve-
shaped
socket region of the socket according to Figure 1 embodies another contact
socket
71A for producing another electrically conductive connection.
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In the sleeve-shaped socket regions of the socket that lie to the left and/or
the right of
the socket flange 76 or at the opposite socket inlets 78, 78A, respectively,
it may
therefore be possible to insert the stripped conductor region of a conductor
61 that is
referred to as the first system element 6 and/or a conductor 81 that is
referred to as
the third system element 8 into the respective socket cavity 72, 72A and to
guide this
(stripped) conductor region along the socket axis (of the entire socket) as
far as the
end of the contact socket 71 that is closed in the center of the socket or the
socket
outlet 74, respectively (such that it is contacted by the conductor end).
According to
the example shown in Figure 1, an electric conductor 61 that is realized in
the form
of a nickel-coated copper conductor and referred to as the first system
element 6
should only be connected to one side of the contact socket 75 that is referred
to as the
second system element 7.
The conductor insulation of the copper conductor may conventionally not be
inserted
into the socket cavity. A more detailed description of (other) distinguishing
peculiarities of cable installations is provided further below.
The electrically conductive connection according to Figure 1 produced by
crimping
the contact socket 71 on the conductor end region accommodated in the socket
with a
suitable crimping tool may be accepted by a person skilled in the art as a
correctly
produced "conductor-socket connection" or a flawlessly produced "electrically
conductive connection 5." A glance into the inspection hole 75 provided on the
contact socket 71 enables the inspector to visually inspect each copper
conductor and
therefore makes it possible to verify that the connection was correctly
produced.
According to the example shown in Figure 2, it is may be known to connect each
aluminum conductor that is realized with a copper and/or nickel coating of the
bunched wires of the aluminum conductor to a contact socket 71, the socket
material
of which significantly differs from that of aluminum according to the may be
known
"electrochemical series". Such cable connections that are produced with system
elements 6, 7 of different materials may ultimately be destroyed because the
material
decomposes due to the inevitably occurring (unavoidable) electrochemical
corrosion
of the (initially realized) electrically conductive connection 5. However,
embodiments of cable connections may also be known (for whatever reasons), in
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which the thusly connected system elements 6, 7 are realized with a silver
socket 141
that adds yet another different conductor material and is referred to as the
fourth
system element 14. The latter is arranged along the socket axis of the contact
socket
71, the conically shaped socket head of which adjoins with its cone point the
closed
socket end (socket outlet 74) that is positioned in the center of the contact
socket 71
and appropriately adapted to the conical shape.
In addition, it is amazing but true that, for example, the stripped conductor
region of
the aluminum conductor is positioned along the socket axis of the silver
socket 141,
wherein the electrically conductive connection 5 of a thusly realized
arrangement is
produced by circumferentially crimping the contact socket 71 on the silver
socket
141, the crimping of which is transmitted to the stripped conductor region of
said
aluminum conductor. A few questions may remain unanswered that exceed the
broader scope of the description, namely because it is not discussed, for
example,
whether the silver socket according to the presented arrangement of the system
elements is able to delay electrochemical corrosion for a sufficiently long
time; or
whether the crimping pressure exerted upon the contact socket 71, for example,
with
a manual crimping tool may be transmitted with sufficient intensity to the
aluminum
conductor used as the electric conductor 61. In any case, Figure 2 makes one
thing
clear: it may be impossible to make any statements that readily provide
answers to
such questions as: "How deep will said copper conductor be seated in the
silver
socket?" or "What maintainable distance will the end of the aluminum conductor
have from the closed socket outlet 74 (situated approximately in the center of
the
contact socket 71)?" It may remain a fact that the inspection hole 75 of the
contact
socket 71 may obstructs the view of the aluminum conductor that remains
blocked by
the additional arrangement of the silver socket 141.
We hope the reader will not be disappointed because no additional embodiments
are
discussed that feature another duplicate silver socket 141A arranged on the
socket
axis of the contact socket 71 in the form of a mirror image of the
aforementioned
silver socket 141.
The reason for this is correlated with the repeated mentioning of the above-
described
disadvantages (of the same type) of a crimpable arrangement (shown on the
left) of
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the system elements according to Figure 2 that may occur as predicted if an
additional copper conductor is connected to the socket in order to produce an
electric
cable connection of the conductor-fitted contact socket 71, for example, with
other
devices, apparatuses, etc.
These disadvantageous deficiencies of the aforementioned cable arrangements
also
apply to known electrically conductive connections 5 according to the examples
shown in Figures 3A, 3B, 3C. However, certain differences may exist (in
comparison
with the description of the embodiment according to Figures 1 and 2),
according to
which a definitively limited insulation region of the conductor insulation 62
of an
electric conductor 61 that is referred to as the first system element 6 is
arranged
underneath a predefined socket (crimping) surface B of the contact socket 71
so as to
prevent or at least restrict an additional admission of moisture or other
liquid or
gaseous fluids after the contact socket 71 has been (sufficiently?) crimped on
the
conductor insulation 62 inserted into the socket. The question whether this
measure
may suffice is not discussed further.
In a thusly crimped connection 5 that is realized, for example, with an
electric
conductor 61 and a contact socket 72 that both consist of an aluminum
material,
however, it may be impossible to visually verify that the end of the electric
conductor
61 accommodated in the socket actually extends as far as the closed socket end
(socket outlet 74) or was arranged such that it adjoins or is positioned a
tolerable
distance Al from this socket end, respectively. The closure of the socket
outlet 74
(i.e., the end of the socket) would be situated underneath an exemplary socket
flange
76 that is annularly arranged on the circumference of the contact socket 71.
Although
the contact socket 71 features an inspection hole 75 (a contact hole for a
visual
inspection) at a defined location, this inspection hole is covered by the
auxiliary
socket 141 used that is realized in the form of a silver socket such that no
visual
inspection may be carried out in order to determine whether the electric
conductor 61
is at least arranged in the socket within the permissible tolerance range.
This is the
reason why one utilizes correspondingly positioned markings 63 that are
(circumferentially or pointwise) arranged (in a clearly visible fashion) at a
defined
location of the conductor insulation 62 in order to ensure the required length
measure
of the conductor insulation 62 and of the electric conductor 61. However, it
may not
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be ruled out that cable connections 5 realized in accordance with the
arrangements in
Figures 3B and 3C are produced because individual or mechanical installation
errors
may still occur. A correctly produced embodiment of a crimped conductor-socket
connection with aluminum system elements 6, 7 is illustrated in Figure 3A. In
comparison with correlating Figure 3C, Figure 4 provides the observer with a
more
detailed overview of an incorrectly produced connection 5.
The preceding (general) remarks regarding the state of the art are provided
for the
better understanding of the testing apparatus 1 described below (with
reference to
Figures 6-8) and the method for detecting (identifying) a contact deficiency
of an
(already crimped) electrically conductive connection 5 (that is implemented
with this
testing apparatus).
According to Figure 6, this testing apparatus I consists of a measuring
chamber 2, a
heat radiator 9, 9R, a positioning and fixing device 18, a thermal (image)
acquisition
unit 11, 11R, a thermal (image) reproduction unit 13, 13R, a thermal (image)
evaluation unit 15 and, if applicable, an external readout display screen 21
that are
connected to one another by a circuit and/or related to one another.
The aforementioned functional elements and other means of the testing
apparatus 1
according to Figure 6, the reference symbols of which are provided with the
index
"R," respectively refer to a heat radiator 9R for infrared light that
transfers thermal
radiation 91R consisting of infrared light and, in addition, to thermal
radiation 29R
that consists of infrared light and is emitted by the thermal field 12R of the
crimped
electrically conductive connection 5 that is derived from the thermal
radiation 91R
for infrared light, as well as to a thermal (image) acquisition unit 11 R for
infrared
radiation and a thermal (image) reproduction unit 13R for infrared light.
This supplementary reference symbol index "R" is also used in the following
Figures
7 and 8 and their description.
One physical embodiment of said testing apparatus 1 is presented in Figure 5,
wherein the functional elements of the testing apparatus I are positioned
within a
chamber wall 4 for the measuring chamber 2, namely in a housing region 16 of a
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housing 7 that borders the latter. The thusly integrated housing 17 of the
testing
apparatus 1 has an appearance that corresponds or is at least very similar to
that of a
camera. In this case, the measuring chamber 2 features an aperture region 2A
that is
framed by the chamber wall 4 on one side of the measuring chamber and
continued
with the walls of the adjacent housing region 16.
With reference to Figure 6 that shows a block diagram and indicates the
approximate
position of the circuit elements in the form of a side view, it may also be
ascertained
that the displaceable positioning and fixing device 18 is arranged on the
bottom of
the measuring chamber 2, wherein the electrically conductive connection 5 that
is
realized by crimping the electric connecting elements (system elements 6, 7
and/or 8)
and needs to be tested for (an) existing contact deficiency (deficiencies) is
fixed on
said positioning and fixing device such that its vertical distance from the
chamber
bottom may be varied. A heat radiator 9, 9R is positioned near the chamber
ceiling of
the measuring chamber 2 at a certain vertical distance from the thusly
positioned test
arrangement (finished electrically conductive connection), wherein said test
arrangement is subjected to the heat of the thermal radiation 9, 91, 91R
directed
thereon.
This may make it necessary to supply the heat radiator 9, 9R with energy from
an
energy source, for example, with the direct current IG of a d.c. generator or
an
accumulator, wherein said energy supply can be selectively interrupted with
the aid
of a first electric switch A. The thermal field acquisition panel 20 is
situated within
the walls of the housing region 16 near the aperture region 2A of the
measuring
chamber 2, wherein the thermal field acquisition panel 20 is directed toward
the test
arrangement (finished electrically conductive connection 5). The latter may be
realized, for example, with heat sensors 19, 19R that are distributed over the
panel
surface and able to optically capture (record) the thermal radiation 29, 29R
of a
thermal field 12, 12R emitted by the conductor insulation 62 of the system
elements
6 and/or 8 as well as the conducting components of the conductive (metallic)
system
elements 6, 7 and/or 8 due to the accumulation of the applied heat, wherein
the
transferred thermal radiation 29, 29R of the thermal field 12, 12R passes
through the
aperture region 2A of the plenum chamber 2 and may ideally be directed
straight on
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the thermal field acquisition panel 20 or the heat sensors 19, 19R distributed
to over
the panel surface thereof and directly recorded.
Suitable downstream units for the signal conversion of the sensed thermal
field 12,
12R are connected to the elements of the thermal field acquisition panel 20 or
the
heat sensors 19, respectively, and form integral components of the thermal
(image)
acquisition unit 11, 11R.
The thermal field 12, 12R of the test arrangement that was acquired with
sensors and
converted, for example, into digital signals is transmitted via an additional
data line
K to the thermal (image) reproduction unit 13, 13R that reproduces a digitally
illustrated thermal image of the testing apparatus with possibly existing
contact
deficiencies of the test arrangement (the crimped electrically conductive
connection
5) with the aid of an integrated thermal image reproduction panel 21B. The
thermal
(image) reproduction unit 13, 13R is laterally arranged on the edge and above
(on the
cover surface of) the housing 17 of the testing apparatus 1, wherein the
thermal
image reproduction panel 21 B is fitted into a housing recess 21 A in the
cover surface
of the housing 17 or positioned underneath the recess 21A. This thermal
(image)
reproduction unit 13, 13R or thermal image reproduction panel 21B,
respectively,
may also (according to this example) be arranged at any other location of the
housing, for example, laterally of the housing 17. The measured values of the
transferred thermal radiation of the thermal field 12, 12A that provides
information,
among other things, on the temperature conditions in the measuring chamber 2
during the test can also be displayed on said thermal image reproduction panel
21B.
In order to enable the thermal image reproduction panel 21 B to also display
other
information in addition to the visual detection of a (correctly or incorrectly
produced)
electrically conductive connection 5 in order to visualize not only the type,
but also
the extent (magnitude) of a contact deficiency, a thermal (image) evaluation
unit 15
may be selectively connected to said thermal (image) acquisition unit 11, 11R
via
data lines H, M (outgoing and incoming lines). The latter may comprise a (not-
shown) storage unit, in which the digital nominal data of a thermal image that
pertains to contact deficiencies is retrievably stored.
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This nominal data is electronically analyzed with the actual data of the
thermal field
12, 12R of the test arrangement that was acquired with the aid of sensors and
digitized, namely by a comparison device that forms part of the thermal
(image)
evaluation unit 15, wherein the (not-shown) comparison device transmits the
result
obtained from the comparison via one of the data lines to the thermal (image)
acquisition unit 11, 11R as shown in the example according to Figure 6 in
order to
make this result available to the thermal (image) reproduction unit 13, 13R.
Otherwise, the comparison device of the thermal (image) evaluation unit 15 may
also
directly transfer the result of the comparison between the nominal data and
the actual
data to the thermal (image) reproduction unit 13, 13R. This makes it possible
to
visually output a determined length difference Al that was analyzed
(determined) to
be a contact deficiency or a tolerated or non-existent length difference on
the thermal
image reproduction panel 21B or on an external readout display screen 21
connected
to the thermal (image) reproduction unit 13, 13R, wherein the determined
length
difference
a) is selected between a conductor end 64 of the conductor 61 and/or 81 that
is
positioned within the socket cavity 72 and along the socket axis E and the
closed
socket end at the socket outlet 74 or between two opposite conductor ends
within the
socket cavity 72 and/or
b) refers to the detection of an insulated conductor region accommodated in
the
socket that is covered with insulation 62 and assigned to a socket (crimping)
surface
B for crimping the insulation that is positioned within the contact socket 71
along the
socket axis F and situated near the socket inlet 78.
Figures 7 and 8 respectively show an embodiment of the testing apparatus 1
with a
measuring chamber 2 according to Figure 6 and a not-shown adjacent housing
region
16 that is protected by walls and forms a complete housing 17 together with
the
measuring chamber. One may ascertain from the illustration in Figure 7 that
the heat
radiator 9, 9R operated according to the example shown in Figure 6 emits
thermal
radiation 9, 9R in the direction of the test arrangement [electric conductor
61,
conductor insulation 62, contact socket 71 with illustrated socket cavity 72,
as well
as socket flange 76 arranged in the center of the socket and (plug-type)
socket
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extension 77 along the socket axis F attached to the latter (to the right of
the contact
socket 71)], wherein this thermal radiation heats the test arrangement and
builds up a
thermal field 12, 12R that is optically captured by an optical device 23 in
the form of
a lens and directed on a plane plate 22, the surface of which is formed by two-
dimensionally distributed heat sensors 27, with the aid of an opened optical
shutter
device 28 that is released during the measuring phase and remains closed
during the
heating phase of the test arrangement. If the times for the opening and
closing
function of the shutter device 28 are not observed, the function of the sensor-
fitted
plate 22 would be jeopardized because it cannot be precluded that this plate
is heated
up (despite planned temperature stabilization) such that the measuring
sensitivity
may be respectively diminished or impaired, comprised image data may be
converted
and faulty images may be produced. Corresponding panel elements 25 for the
temperature stabilization are two-dimensionally distributed underneath the
plate 22
such that a "Focal Plane IR Panel-with temperature stabilization" is formed.
An electronics unit 24 arranged downstream of the heat sensors 27 is also
referred to
as the "camera electronics" and completes the functions of a thermal (image)
acquisition unit 11, 11 R that is already known from the description of Figure
6. In
addition, the distance a assumed between the lens and the plate 22 is shown.
These
figures also show the connection between said electronics unit 24 and the
thermal
(image) reproduction unit 13, 13R, on the thermal image reproduction panel 21B
of
which a readout display screen 21 with a graphic illustration is reproduced
that
pertains to an incorrectly produced electrically conductive connection 5
according to
the example shown in Figures 3C and 4.
In contrast to the embodiment according to Figure 7, the embodiment shown in
Figure 8 is designed for electrically heating the test arrangement described
with
reference to Figures 7 by means of an energy source (d.c./a.c.) such that the
installation of a heat radiator 9, 9R may not be required. All other functions
of the
test arrangement 1 described with reference to Figure 7 are equally realized.
The presented testing apparatus 1 and the correlating method for detecting a
contact
deficiency of an electrically conductive connection 5 may be summarized in a
simplified fashion as follows.
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An electric conductor 61 that is incorrectly inserted into the contact socket
71 results
in an air gap Al between the conductor end situated within the socket cavity
72 and
the contact socket. This air gap Al has an inferior coefficient of thermal
conductivity
in comparison with the metallic components of the electrically conductive
connection 5 (electric conductor 61, contact socket 71) that are connected by
crimping. Due to the heating of the crimp connection, thermography makes it
possible to visualize whether an unacceptable air gap Al is present that would
result
in inferior contacting of the connection 5. In addition, the converted
deficiency
image according to Figures 6-8 may make it possible to deduce that a crimp of
the
conductor insulation (an insulation crimp) that is realized, for example,
according to
Figure 3B has an insufficient crimpable surface and therefore tends to develop
the
described leaks of the electrically conductive connection 5 that are
associated with
the risk of undesirable corrosion, for example, due to the admission of
atmospheric
humidity or other corrosive gaseous pollutants into the socket cavity 72.
According to the example shown in Figure 7, the following test steps of a
simplified
method for detecting contact deficiencies of a cable connection may be carried
out in
the described sequence, wherein
a) the crimp connection 5 (electric conductor 61 with contact socket 71) is
fixed
in a measuring chamber 2;
b) the cable connection 5 is then heated to a certain temperature by a heat
radiator 9;
c) the heating of the connection 5 is subsequently shut off after the metallic
components of the electrically conductive connection 5 have reached the
temperature t;
d) the optical shutter device 28 is then opened;
e) a thermal image is recorded by means of a so-called IR array;
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f) the signal information of the IR array is subsequently converted in an
electronics unit 24 (in the camera electronics), and
g) the thermal image is ultimately displayed on a thermal image reproduction
panel 21B (a screen).
With respect to the above-described method for detecting contact deficiencies
of a
cable connection, the test step described below may be substituted -referred
to the
illustration shown in Figure 8- for step b) as follows
h) the cable connection 5 with a generator-fed energy source 10 connected
thereto is then supplied with a current and heated to a certain temperature.
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List of Reference Symbols
1 Testing apparatus
2 Measuring chamber
S 2A Lateral aperture region
3 Aperture region (of measuring chamber 2)
4 Chamber wall (of measuring chamber 2)
Electrically conductive connection
6 First system element
61 Electric conductor
62 Conductor insulation
63 Marking (of conductor insulation 62)
7 Second system element
71 Contact socket
71A Contact socket
72 Socket cavity
72A Socket cavity
73 Socket wall
74 Closed socket outlet (socket end)
75 Inspection hole (of contact socket 71)
76 Socket flange
77 Socket extension, plug-type
78 Socket inlet
78A Socket inlet
8 Third system element
81 Electric conductor
9 Heat radiator
9R Infrared light heat radiator
91 Transferred thermal radiation
91R Transferred thermal radiation--consisting of
transferred infrared light
10 Energy source; generator; d.c. generator
11 Thermal (image) acquisition unit
1 IR Thermal image acquisition unit for infrared light
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12 Thermal field
12R Thermal field--derived from thermal radiation for infrared light
13 Thermal (image) reproduction unit
13R Thermal (image) reproduction unit for infrared light
14 Fourth system element
141 Auxiliary socket; silver socket
14A Duplicate of fourth system element 14
141A Duplicate of auxiliary socket 141; silver socket
Thermal (image) evaluation unit
10 16 Housing region (of housing 17) protected by walls
17 Housing (of testing apparatus 1)
18 Positioning and fixing device
19 Heat sensors
Thermal field acquisition panel
15 21 Readout display screen
21A Housing recess
21B Thermal image reproduction panel
22 Plate, plane
23 Optical device; lens
20 24 Electronics unit
Panel element, temperature-stabilized
26 Heat sensor array
27 Heat sensors
28 Optical shutter device
25 29 Thermal radiation
29R Thermal radiation
A, D Switch
B Socket (crimping) surface for insulation crimp
C Conductor end region (of conductor 61, 81)
F Socket axis
G Index: generator
H, M Data line
I Electric current, constant
K Data line
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S Air gap
a Distance (plate 22-optical device 23)
b (Pre)defined length [of socket (crimping) surface B]
I Stretched element length (of the system elements 6-8 in the measuring
chamber 2)
liso Required insulation length (of conductor insulation 62)
